1. Field of the Invention
The present invention relates to a recording system or an image transfer system which includes an exposing device for image-wise exposing a pressure-sensitive photosensitive medium having a layer of a chromogenic material or color precursor, so as to form latent images corresponding to desired source image information, and a developing device for applying a pressure to the image-wise exposed photosensitive medium so as to cause a chemical reaction with a developer material provided on the photosensitive medium or on a separate recording medium, so that the latent images are developed into visible images.
2. Discussion of the Prior Art
In a known recording system of the type indicated above, a chromogenic material or color precursor capable of reacting with a developer material so as to produce a color image is contained in each of a multiplicity of microcapsules which constitute a microcapsule layer on a pressure-sensitive photosensitive medium. In one form of this type of photosensitive medium, the microcapsules further contain a resin which supports the chromogenic material and whose mechanical strength is varied upon exposure to a radiation. In another form of the photosensitive medium, the mechanical strength of the microcapsules containing the chromogenic material is varied upon exposure to a radiation. In either case, the microcapsules whose mechanical strength after exposure to a radiation is comparatively low are ruptured, to permit the chromogenic material to come out from the ruptured microcapsules, whereby the chromogenic material chemically reacts with the developer material, so as to produce a color image.
The developer material is provided either as a developer layer formed on the substrate of a photosensitive medium, or alternatively as a separate developer sheet which is superposed on the photosensitive medium when the latent images on the photosensitive medium are developed into the visible images on the developer sheet. In the former case, the visible images are formed on the photosensitive medium having the developer layer. This type of photosensitive medium is a so-called "self-activated" type. In the latter case, the photosensitive medium is used as a transfer sheet while the developer sheet is used as a recording medium on which the visible images are eventually formed. This latter arrangement is referred to as a "separate" type.
An example of the self-activated type of photosensitive medium is disclosed in U.S. Pat. No. 4,440,846, while an example of the separate type is disclosed in U.S. Pat. No. 4,399,209.
In both cases indicated above, the photosensitive medium having a microcapsule layer is image-wise exposed in a suitable manner. For example, the photosensitive medium is exposed to a radiation which is reflected by an original bearing desired source image information, or which is transmitted through the original. In the former case, the photosensitive medium and the original may be held in close contact with each other. The developing device for pressing the image-wise exposed photosensitive medium may use suitable pressing means such as presser rollers, impact head, or rotating balls.
As indicated above, the known recording system of the type described uses either a self-activated photosensitive recording medium, or a combination of a photosensitive medium without a developer layer and a separate recording medium with a developer layer. In either case, therefore, the user of the recording system has to use the exclusively designed photosensitive recording medium or developer sheet, on which desired images are eventually formed. In other words, the user cannot copy desired images on a desired recording medium such as commercially available ordinary papers, postcards, fabrics, plastic films or sheets, or other planar members made of other materials. If the user wishes to have the desired images formed on a desired recording medium, the images must be first formed on a self-activated photosensitive medium or a developer sheet, and the imaged medium or sheet must then be bonded to the surface of the desired medium such as a postcard. This procedure is time-consuming, and results in the finally obtained medium having an increased thickness.